It's an interesting idea to use a cheetah, but I thought it looked a bit more like a kangaroo, and I didn't really understand, maybe illustrate the cheetah while it's in its stretched out running form and it will be easier to recognize. The concept is great, though. I would wear this if the cheetah were fixed.

It looks like clip art for 2 reasons I think. 1) Because the style of the head is in outline, whereas the hand is in silhouette and the cheetah is a weird combo of the two. 2) The shirt features 3 separate images that don't have much of a real connection (the speech bubble doesn't line up right with the mouth and the cheetah is just kinda floating off to the side).

Plus, the middle graphic and the cheetah are redundant, as both imply talking fast--go with one or the other.

In conclusion: use similar styles, ditch one of the images on the left and then try to integrate the pictures into one image as opposed to 2 pasted next to eachother.